Police have issued an arrest warrant for the suspect in a mass shooting at Brown University that killed two people and injured nine others, sources close to the investigation told the BBC's US partner, CBS News.

Authorities are now searching for the individual and a car the suspect is believed to have rented. They have not publicly identified the suspect.

The investigation is exploring a possible connection between the shooting at Brown and the killing of a professor at the Massachusetts Institute of Technology (MIT) that occurred just two days later.

The search enters its sixth day, with investigators going door-to-door, gathering home-security footage, and appealing to the public for tips to track down the gunman.

An anticipated news conference by the Providence police was abruptly canceled, but officials indicated an update would follow soon.

On Thursday, police began investigating potential connections between the Brown shooting and the killing of Nuno F Gomes Loureiro, a 47-year-old MIT professor, who was shot multiple times at his home in Brookline, Massachusetts.

A rental car matching the description seen at both crime scenes has become a focal point for investigators.

Federal authorities had previously stated that there was no evident link between the two incidents. However, unearthed evidence now prompts a reassessment as police seek anyone who may have critical information.

Police Chief Oscar Perez stated that the suspect “could be anywhere,” expressing uncertainty regarding the suspect’s current location and identity.

Police released footage of a person of interest who was seen wearing a mask near the university campus, possibly surveilling the area before the attacks.

Community members have voiced frustration over the slow progress in the investigation, leading Rhode Island Attorney General Peter Neronha to assure that the investigation would yield results and that “it is just a matter of time before we catch him.”

The FBI has announced a $50,000 reward for information that leads to the identification, arrest, and conviction of the individual responsible for the assault.

The mass shooting transpired at Brown University's Barus & Holley engineering building amidst final exam periods, resulting in the deaths of two students: Ella Cook, a sophomore from Alabama, and Mukhammad Aziz Umurzokov, a freshman student of Uzbek-American descent.